Production of crepelike textile webs



Patented Nov. 12,1940

UNITED STATES PATENT OFFICE".

Rcn Clavel, Angst, near Base], and Theophil Stanisz, Basel, Switzerland,assignors to Far berei-und Appretur-Gesellschaft Vorm. A.

Clavel und Fritz Lindenmeycr, Basel, Switzerland - Claims.

Acetate artificial silk (cellulose acetate silk) textile webs havingcrepe effects have hitherto only been produced in practice by usinghighly twisted threads. This relatively expensive proc- 5 es onlyenables crepe effects of a simplekind to be produced and isnot suitablefor the Production of webs having numerous variations or for theproduction or cloque effects and the like.

The object of this invention is to produce acetate artificial silktextile webs having a lustrous or dull finish and provided with crepeeffects with the employment of untwisted or only slightly twistedacetate threads.

The invention depends on the fact that it is possible on the one hand bytreating acetate silk threads with suitable chemicals to cause them toshrink to a desired, even very considerabladeree, and the fact that onthe other hand it is possible so to protect the acetate silk threads bytreatment with suitable protective substances (reserves), that they donot undergo shrinkage by the action of chemicals in themselves adaptedto shrink acetate silk threads.

According to-this invention therefore by working up protected anduntreated acetate silk 7 threads together it is possible to produceproducts of the desired kind-by treating the same with shrinking-agents,which cause the untreated acetate silk threads to shrink and thereby toproduce the most varied crepe efiecrs and the like, owing to thenon-shrinkage of the protected threads.

7 As protective agents (reserves) for the acetate threads use ispreferably made of phenols,

which contain free active OH groups, i. e. possess a phenolic character,for example tannin.

groups, are capable of being fixed by the cellulose acetate. In this wayprotective efiects based on chemical reactions may be obtained.

' Such compounds, for example condensation products of phenol andresorcinol with formaldee y also be e p y d a u phoaated condition inthe form of suitable emulsions or suspensions, resembling the dvestufl'emulsions employed-for the dyeing of acetate silk.

As shrinkin agents use is preferably made of acid liquids of suitableconcentrations, which 5 i do not attack the cellulose acetate under theworking conditions, for example about 23-26% hydrochloric acid, about-68% phosphoric acid or about 38-48% acetic acid. In addition toinorganic and organic acids, alkali and alkaline 10 earth thiocyanatesmay also be employed inter aliav as shrinking agents. The shrinkingagents must be employed at moderate temperatures, preferablytemperatures not exceeding about 20 C., for example at a roomtemperature of about 15 18 to 20 C. The length or treatment must be suchthat the cellulose acetate is not attacked to any destructive extent. Asa rule a working period of a few minutes sufiices.-

The following example serves to illustrate how 20' the process of thisinvention may be carried into effect:

Acetate silk in hank form is saturated with an aqueous solution whichcontains about 200 gms. of tannin, 10 gms. oi concentratedformic acid 25and gms. of water per litre, in order to protect it from shrinking. The,acetate silk 'is treated in the cold, centrifuged, dried and. ifnecessary treated Ifor a short time longer with steam under pressure,for example issteamed .30 for about 15 minutes in a closed vesselatfabout 108 0., in order to efiect thorough fixing.

After the treatment with protective agents, the acetate silk isadvantageously treated with a suitable dressing solution, for example anap- 35 I proximately 3% -wax and paraflin solution in organicsolvents,'such as benzine, benzene and the like. The threads are therebyrendered more adaptable for further treatmentpfor exmost varied efiectsmay be obtained by varying 50 the arrangement of the protected threadsand the untreated threads relatively to one another and the relativeproportions of the protected threads to the untreated threads. In eneralit has proved to be advantageous to employ in the 66 weft or the warp orin both about 5-10 protected threads to about 3-8 untreated threads.

The webs produced from protected and untreated threads by weaving or thelike are then treated with shrinking agents, preferably acid shrinkingagents, the working conditions, for example with regard to concentrationof the solution, time of treatment and temperature being so selected,that on the one hand shrinkage of the untreated threads to the desireddegree takes place, whilst on the other hand the cellulose acetate isnot attacked or otherwise influenced to a destructive extent. Shrinkingeffects from about to about 50% may be obtained according to theinvention in the weft and the warp, depending on the conditionsselected. Depending on the degree of shrinkage of the untreated threads,the protected, non-shrinking threads or thread parts are more or lessraised and thereby more or less pronounced crepe effects are produced.

The treatment of the fabric with the shrink--,

ing liquid,'for example about 25% hydrochloric acid, is for examplecarried out as follows:

The pieces, bands or the like are left for up to 5 minutes in the acidat a temperature which must not exceed C., for example at a roomtemperature of about 18 C., then freed in a loose condition fromadhering hydrochloric acid, for example by washing in a container withflowing Water and are then with advantage further subjected to anafter-treatment in a weak alkaline liquid for example in a bath whichcontains a solution of 3 gms. of sodium carbonate per litre, in order toefiect neutralisation. If desired the reserves may at the same time beremoved from the threads by this alkaline after-treatment. In order toachieve this result the operation is with advantage carried out atelevated temperatures, for example temperatures of about 40-50 C. Theremoval'of the reserves may also be effected with other agents, forexample soap lyes.

The drying of the pieces is with advantage effected by allowing them toshrink unhindered in a loose condition on suitable bases, for exampletables. The pieces may be allowed to dry slowly at room temperature orslightly elevated temperature or they may be subjected to more rapiddrying by the action of higher temperatures,for example temperatures upto about 90 C.

The 'process may with advantage be carried out with the employment orco-employment of the so-called continuous apparatus. The treatment ofthe pieces with aqueous hydrochloric acid may for example be carried outin accordance with the continuous process, care being taken in this casealso to ensure that they do not stay'for more than about 5 minutes inthe acid solution, since otherwise the hydrochloric acid might exert adisturbing efi'ect. The drying may likewise take place in accordancewith the continuous process, for example by bringing the pieces in aloose condition on to an endless belt onto'which hot air is blown.Alternatively the endless belt may be passed through a hot chamber,through which for example hot dry air is circulated.

It is essential, during the hydrochloric acid treatment and thefollowing wet and dry treatments, to avoid stretching, particularlyconsiderable stretching. of the web. This is particularly the case whenemploying the continuous process. Drying on rods must be avoided;because the fabric is easily stretched thereby and the crepe effects,designs, etc. may be distorted,

Crepe effects may for example be obtained by the process of thisinvention by using only protected and untreated acetate silk threads forthe warp and only ordinary (untreated) or only protected threads for theweft. Similarly crepe effects may for example be obtained by using onlyordinary (untreated) acetate silk threads or only protected threads forthe warp and desired combinations of protected and untreated threads forthe weft. Particularly pronounced crepe effects are obtained by usingordinary threads and protected threads for the warp and weft in suitablearrangements and proportions.

By employing a relatively large number of untreated threads in additionto a relatively small number of treated threads, so-called faconneteffects (striped effects) may for example be obtained in a very simplemanner. In order to obtain special effects, the threads to be protectedmay for example be treated with weaker solutions, than are necessary forproducing complete protection, or different threads may be treated withprotective solutions of different strengths or one and the same threadmay be treated in diiferent parts with protective solutions of dif-.ferent strengths. A further alternative when protecting hanks of threadsis for example to treat these hanks only in parts with the protectivesolution, so that in the treatment of the fabric with shrinking liquidsthese threads remain unchanged in the protected parts and shrink in theunprotected parts.

So-called cracknel effects may for example also be obtained by twistingtogether protected acetate silk threads and untreated threads and thenweaving or knitting the twisted threads. On treating the resultingproducts with shrinking liquids, the unprotected threads are shortenedand thereby the cracknel effect is obtained.

Further researches have shown that in place of the acetate silk threadsprotected according to the invention textile threads of other kinds maybe employed or co-employed with protected acetate silk threads. It hasbeen found that threads i of for example natural silk (schappe), wool,cotton, linen, cellulose artificial silk and other natural andartificial textile threads, when subjected to the process of thisinvention, behave in the same manner as protected acetate silk threads,in that during the treatment of the mixed fabric with liquids whichshrink ordinary (untreated) acetate silk threads, they undergo noshrinkage or no detrimental shrinkage. Thus fabrics and the likeproducts may be manufactured with the production of crepe effects of themost varied kinds, by efiecting the formation of the crepe patterns byshrinking ordinary (untreated) acetate silk threads whilst the remainingthreads, which do not or only in part participate in the shrinkingprocesses, may consist of other textiles of the most varied kinds, ifdesired a plurality of such textiles. Accordingly mixed webs ofcellulose acetate threads and other kinds of threads, for examplenatural silk, wool or cotton threads, if desired a plurality of suchthreads, may accordingly be produced in a very' reserves, which efiectsuitable protection against shrinkage, and then'subjecting the printedtextiles to the shrinking process with the use of suit-- able shrinkingagents, for example about 25% hydrochloric acid. In this way it ispossible to print designs of the desired kind on the materials undertreatment by the usual methods, for example with the aid of printingmachines, stencils or by hand, and thereby to protect the printed partsagainst shrinkage.

Protective agents of the aforesaid kinds, such as tannin or tannin-likesubstances, may also be employed in this case as reserves. When usingthe solutions for printing, they are adjusted to the desired degree ofviscosity, for example with the aid of gum arabic or gum Senegal.

-A reserve adapted for machine printing may for example havethe'following composition:

200 gms. of commercial tannin, 100 gms. of 50% acetic acid, 150 gms. ofwater and 550 gms. of gum.

For carrying out the printing process use may also be made ofmechanically acting protective substances, for example natural orsynthetic resins, waxes, paramns and the like, for example anapproximately solution of colophony in organic solvents, such as xylene.

In this case also the webs after application of the reserves and dryingmay be steamed in order to improve the fixing.

The treatment of the webs with shrinking agents may be effected in thehereinbefore described manner. By the action of the shrinking agent thenon-protected parts of the materials are swollen and shrunk and thefibres shortened. It is consequently possible to produce in a verysimple manner special eifects, such as patterns in relief or crepedesigns.

In this embodiment of the invention also fab= rics may be employed,which, in addition to cellulose acetate threads, also contain threads ofother kinds. Similarly, webs may be employed, which, in addition toordinary (untreated) acetate threads, also contain acetate threadsprotected according to the invention in the warp or weft or both.Finally the webs may also contain ordinary acetate threads, protectedacetate threads and threads of other kinds.

The acetate webs or acetate-containing webs, before or after printingwith the reserves, may

be dyed or printed with colours, or alternatively colours may be appliedsimultaneously with the printing of the reserves.

When employing coloured reserves, adjuvents, for example a littleacetin, are with advantage added to the colour. Coloured varnishes areformed thereby, which during the treatment of the webs with shrinkingagents, particularly acids, are extremely resistant thereto, are notremoved during the treatment with shrinking agents and subsequenttreatments and do not bleed during the shrinking operation on to theunprinted parts. The webs produced by printing may be treated in theusual manner, for example steamed, washed and finished.

The invention, as has been shown, enables the most varied kinds ofefiects to be produced, including those, which it was hitherto notpossible to obtain with the simplest and cheapest means. The productsproduced according to this invention may be treated by the usualmethished:

What we claim is:

1. Process for producing textile goods having a crepe efiect includingthe steps of treating a fabric with hydrochloric acid of a strength ofabout 23-26% at temperatures of not above 20 C., said fabric consistingof threads or thread portions which become shortened by the action ofhydrochloric acid of about 26% and of threads or thread portions whichhave been rendered resistant to ,the action of hydrochloric acid bytreatment with tannin, removing the hydrochloric acid, drying thefabric, the whole treatment being for the purpose of shortening by theabove recited treatment with hydrochloric acid the threads or threadportions which have not been rendered resistant.

2. Process for producing textile goods having a crepe effect includingthe steps of treating a fabric with hydrochloric acid of a strength ofabout 23-26% at temperatures of not above 20 C., said fabric consistingof threads or thread portions which become shortened by the action a ofhydrochloric acid of about 26% and of threads or thread portions whichhave been rendered resistant to the action of hydrochloric acid bytreatment with tannin, the entire treatment being for the purpose ofshortening by the above recited treatment with hydrochloric acid thethreads or thread portions that have not been rendered resistant.

. 3. A process for the production of textile products, such as .textilewebs, having crepelike effacts, which comprises working up acetate silkthreads, which have been protected by pre-treatq ment against shrinkage,with ordinary untreated acetate silk threads into the product, andtreating the product with agents which cause the untreated acetate silkthreads to shrink, the acetate silk threads to be protected againstshrinkage being subjected to a treatment with natural tanrun.

4. A process for the production of textile products, such as textilewebs, having crepelike effects, which comprises working up acetate silkthreads, which have been protected by pre-treatment against shrinkage,with ordinary untreated acetate silk threads into the product, andtreating the product with agents which cause the untreated acetate silkthreads to shrink, the acetate silk threads to be protected againstshrinkage being treated with synthetic products con- .taining activehydroxyl groups and natural tannm.

5. A process for the production of textile products, such as textilewebs, having crepelike effects, which comprises working up acetate silkthreads, which have been protected by pro-treatment against shrinkage,with ordinary untreated acetate silk threads into the product,,andtreating the product with agents which cause the untreated acetate silkthreads to shrink, the agent which is employed for protecting the web inplaces against shrinkage is a resin containing natural tannin.

